DE 10 2007 029 140 and DE 10 2008 048 835 each discloses a lighting device having a plurality of light-emitting diodes in a ceiling element, in which each light-emitting diode is connected to a voltage source via in each case two electric cables. For each light-emitting diode, the lighting device has a holder, which holds a light-emitting diode in a desired position in the lighting device. Furthermore, the lighting device has a plurality of cable guides, which prevent the electric cables from passing too close to or touching the light-emitting diodes, which can lead to a cable defect due to overheating or covering of the emitting surface of the light-emitting diodes. It is a disadvantage of the known lighting device that the outlay for its production is relatively high, because the light-emitting diodes and cables must be fitted into the lighting device, or connected to the holders, by hand, and automated production is not possible.
This known lighting device is used in aircraft cabins to produce a simulated starry sky. The simulated starry sky is thereby produced by the lighting device, which has several hundred light-emitting diodes and is mounted on an interior trim panel. In order to produce such a lighting device, the several hundred light-emitting diodes with the associated copper cables must be fitted, or laid, by hand. This requires a high outlay in terms of time. In addition, manual production gives rise to a high error potential (for example when determining the cable lengths and producing the electrical connections between the cables and the light-emitting diodes), so that follow-up work is frequently necessary.
The known lighting device additionally has a relatively high weight owing to the large number of components such as light-emitting diodes, copper cables, holders and cable guides which are used. The large number of copper electric cables in particular leads to an increase in the weight. Furthermore, the known lighting device requires a relatively large amount of space because of the size of the light-emitting diodes with cables soldered to their pins, so that the cabin height is reduced when the known lighting device is used in an aircraft cabin to produce a simulated starry sky.
Also known are electroluminescent films, in which a layer consisting of an electroluminescent material is excited to emit light radiation by an alternating electrical field produced by two electrode layers. In the electroluminescent films, the layer of electroluminescent material and the electrode layers have the same dimensions and are arranged congruently one above the other, so that an electroluminescent film forms a flat light source. Electroluminescent films are flexible but can only be applied to simple three-dimensional bodies, such as, for example, a circular cylinder. Application to more complex three-dimensional bodies, such as, for example, a sphere, is not possible. Moreover, electroluminescent films have a relatively large thickness and a relatively high weight, which makes their use unattractive in particular in aircraft cabin construction.
The invention is directed to the object of providing a lighting device having a plurality of light sources, which can be produced in a simple manner, has a low weight, is space-saving and can be applied in a simple manner to complex three-dimensional bodies.
In order to achieve that object, a lighting device having a plurality of light sources is provided, the lighting device comprising several superimposed layers, having a first and a second electrically conductive layer, which are configured to produce an alternating electrical field between them, an electrically insulating layer between the electrically conductive layers, and a luminescent layer between the electrically conductive layers, wherein electroluminescent material is arranged within the luminescent layer in several spatially separated regions, each of which forms a light source. The spatially separated regions are arranged in the luminescent layer in different planes.